The present invention concerns a reciprocating compressor with a compression chamber used in an air conditioner, refrigerator, freezer and the like, and more particularly an intake and a discharge valve for respectively controlling a refrigerant flowing into the compression chamber through an intake orifice and discharged out through a discharge orifice.
Generally a reciprocating compressor used in a refrigerator is to compress a refrigerant with a high pressure, which then is cycled through condensation, expansion and evaporation. A conventional reciprocating compressor comprises, as shown in FIG. 4, a sealed housing 10 having an intake tube (not shown) and a discharge tube, a drive 30 provided in the housing for generating power, and a compression part 20. The drive 30 comprises a stator 31, a rotor 32, a rotating shaft 34 mounted to the rotor 32 by means of a pressure fit, and an eccentric shaft 33 integrally formed with the lower end of the rotating shaft. The compression part 20 further comprises a hollow cylinder block 22 mounted on the lower side of the drive 30 with both sides opened, a cylinder head 23 for closing one opened side of the cylinder block 22 to form a cylinder bore 21 to serve as a compression chamber, a piston 24 for reciprocating in the compression chamber 21 to intake, compress and discharge the refrigerant, and a connecting rod 25 extending into the other opened end of the cylinder to block for converting the eccentric rotational motions of the eccentric shaft 33 into rectilinear motions. In addition, the cylinder head 23 has an intake chamber 27 and a discharge chamber 26 for respectively guiding the intake and discharge of the refrigerant into and from the compression chamber 21. A main valve plate 50 is mounted between the cylinder head 23 and the cylinder block 22, having an intake value 2 and a discharge valve; as shown in FIG. 5, to selectively connect the compression chamber 21 with the intake chamber 27 or the discharge chamber 26.
In such a conventional reciprocating compressor, if the interaction between the stator 31 and the rotor 32 causes the rotating shaft 34 and thus the eccentric shaft 33 to rotate, the eccentric rotational motions of the eccentric shaft 33 are converted into the rectilinear reciprocating motions by the connecting rod 25, so that the piston 24 rectilinearly reciprocates in the compression chamber 21, thus sucking the refrigerant through the intake chamber 27 into the compression chamber 21, compressing and discharging it through the discharge chamber 26 into the inside of the sealed housing 10. The compressed refrigerant is finally supplied to the refrigerating system through a discharge tube (not shown).
The, the main valve plate 50 interposed between the cylinder block 22 and the cylinder head 23, has an intake orifice 51 and a discharge orifice 52 for respectively connecting the compression chamber 21 with the intake chamber 27 and the discharge chamber 26. An intake valve plate 54 having the intake valve 2 integrally formed is mounted on the inner side of the main valve plate 50 toward the compression chamber 21 so that the intake valve 2 may selectively open or close the intake orifice 51. On the other hand, the discharge valve 1 is mounted on the outer side of the main valve plate 50 toward the discharge chamber 26 so as to selectively open or close the discharge orifice 52 alternately with the opening or closing of the intake orifice 51. Additionally, there are gaskets 57 and 58 respectively mounted on both sides of the main valve plate 50 to prevent leakage of the refrigerant. The intake and discharge valves 2 and 1 are made of a resilient material to make it possible to open or close the intake and discharge orifices 51 and 52 according to the pressure variations of the compression chamber 21.
Moreover, referring to FIG. 6 for illustrating the structure of the discharge valve 2, one end part of the discharge valve 2 is mounted on the main valve plate 50 so that the other end can completely close the discharge orifice 52, and its opening range is restricted by a stopper 55 mounted over it. Also mounted over them is a keeper 56 to fix them.
In operation of such conventional intake and discharge valves, when the piston 24 is moved toward the left side (bottom dead center) with reference to FIG. 4, and the pressure of the compression chamber 21 becomes lower than that of the intake chamber 27, the intake valve 2 is opened toward the compression chamber 21, thus admitting refrigerant into the compression chamber. Then, when the pressure of the compression chamber 21 attains the same level to that of the intake chamber 27, the intake valve 2 resiliently returns to the original position to close the intake orifice 51. When the piston 24 keeps on moving toward upper dead center after passing bottom dead center, compressing the refrigerant, and the pressure of the compression chamber 21 becomes greater than that of the discharge chamber whereupon, the discharge valve 1 is opened to discharge the compressed refrigerant through the discharge orifice 52 to the inside of the sealed housing.
Such conventional intake and discharge valves suffer the drawbacks that oil films usually formed between the intake and discharge orifices and the intake and discharge valves impede the opening operation of the valves, thus requiring greater forces to open the valves than would otherwise be the case, so that the working efficiency of the compressor is reduced. Besides, the discharge valve is pressed by the stopper as shown in FIG. 6, requiring an additional force to open.